Not all biodegradable teabags will fully decompose, finds UCC study

The research, from University College Cork, compared the degradation of teabags from eight different brands commonly found on Irish shelves.
Not all biodegradable teabags will fully decompose, finds UCC study

The study focused on the sealant that bonds the tea bag and whether or not it is biodegradable.

A NEW study focusing on teabags has found that not all biodegradable teabags on the market will fully decompose.

The research, from University College Cork, compared the degradation of teabags from eight different brands commonly found on Irish shelves.

The study focused on the sealant that bonds the tea bag and whether or not it is biodegradable.

The majority of teabags on the market contain a plastic called polypropylene (PP) as a sealant.

Recently, some major Irish tea brands have started to switch to alternative materials made of plants, like cellulose or the so-called “bioplastics” like polylactic acid (PLA).

For the study, teabags were individually buried outdoors in garden soil in Cork city during 2020 and 2021 and checked periodically for one year. After a year, all teabags and their fragments were measured and visualised using a powerful microscope to look for signs of degradation.

The main findings of the study show that after 12 months in soil, teabags made of a blend of cellulose and PP (conventional plastic), the most common teabag found in supermarkets, had produced the highest number of fragments. This was expected, as plastics are known to degrade into smaller fragments called microplastics.

Interestingly, teabags made entirely of PLA (‘bioplastic’), which were marketed as completely biodegradable, were still found completely intact in soil.

However, not all teabags behaved the same and some did biodegrade in soil.

The teabags made entirely of cellulose biodegraded within three weeks, while those made from a blend of cellulose and PLA (bioplastic) biodegraded in 3.5 months. That’s because the blend contains PLA in only a very small ratio, meaning that the teabag is mostly made of cellulose which is known to degrade very fast.

The study is published in the journal Frontiers in Bioengineering and Biotechnology.

This study was part of a project funded by Ekaterra, the research was independently controlled by the author.

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